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80 lines
3.2 KiB
EmacsLisp
80 lines
3.2 KiB
EmacsLisp
;;; shorthands.el --- Read code considering Elisp shorthands -*- lexical-binding: t; -*-
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;; Copyright (C) 2021-2023 Free Software Foundation, Inc.
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;; Author: João Távora <joaotavora@gmail.com>
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;; Keywords: lisp
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software: you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
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;; (at your option) any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
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;;; Commentary:
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;; Basic helpers for loading files with Shorthands.
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;;; Code:
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(require 'files)
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(require 'mule)
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(eval-when-compile (require 'cl-lib))
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(defun hack-read-symbol-shorthands ()
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"Compute `read-symbol-shorthands' from Local Variables section."
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;; FIXME: relies on the `hack-local-variables--find-variables'
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;; detail of files.el. That function should be exported,
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;; possibly be refactored into two parts, since we're only
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;; interested in basic "Local Variables" parsing.
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(alist-get 'read-symbol-shorthands (hack-local-variables--find-variables)))
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(setq hack-read-symbol-shorthands-function #'hack-read-symbol-shorthands)
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;; FIXME: move this all to progmodes/elisp-mode.el? OTOH it'd make
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;; more sense there, OTOH all the elisp font-lock stuff is actually in
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;; lisp/emacs-lisp/lisp-mode.el, which isn't right either. So
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;; shorthand font-locking logic is probably better here for now.
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(defface elisp-shorthand-font-lock-face
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'((t :inherit font-lock-keyword-face :foreground "cyan"))
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"Face for highlighting shorthands in Emacs Lisp."
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:version "28.1"
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:group 'font-lock-faces)
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(defun shorthands--mismatch-from-end (str1 str2)
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(cl-loop with l1 = (length str1) with l2 = (length str2)
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for i from 1
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for i1 = (- l1 i) for i2 = (- l2 i)
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while (and (>= i1 0) (>= i2 0) (eq (aref str1 i1) (aref str2 i2)))
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finally (return (1- i))))
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(defun shorthands-font-lock-shorthands (limit)
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(when read-symbol-shorthands
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(while (re-search-forward
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(concat "\\_<\\(" (rx lisp-mode-symbol) "\\)\\_>")
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limit t)
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(let* ((existing (get-text-property (match-beginning 1) 'face))
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(probe (and (not (memq existing '(font-lock-comment-face
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font-lock-string-face)))
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(intern-soft (match-string 1))))
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(sname (and probe (symbol-name probe)))
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(mm (and sname (shorthands--mismatch-from-end
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(match-string 1) sname))))
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(unless (or (null mm) (= mm (length sname)))
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(add-face-text-property (match-beginning 1) (1+ (- (match-end 1) mm))
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'elisp-shorthand-font-lock-face))))))
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(font-lock-add-keywords 'emacs-lisp-mode '((shorthands-font-lock-shorthands)) t)
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;;; shorthands.el ends here
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